Means of attachment for screen leaf springs



J. L. RAPP June 19, 1945.

vMEANS oF ATTACHMENT FOR SCREEN LEAF SPRINGS ls sheets-sheet 1 FiledMarch 15. 1945' J. L. RAPP v June'19, 1945.

MEANS OF ATTACHMENT 'FO SCREEN LEAF SPRINGS 3. Sheets-Sheet 2 FiledMarch 15, 1943 June 19, 1945.. J. l.. RAPP 2,378,499

MEANS 0F ATTACHMENTlFOR SCREEN LEAF'SPRINGS l Filed March l5, 1943 3Sheets-Sheet 3 Patented June 19, 1945 MEAN OF ATTACHNIENT FOR SCREENLEAF SPRINGS John L. Rapp,

Milwaukee, Wis., assigner to Nordberg Manufacturing Company, Milwaukee,Wis., a corporation of VllisconsinA f Application March 15, 1943, SerialNo. 479,169 (cl. 20a-415) 14 Claims.

My invention relates tov an improvement in vibrated screens and has forone object to provide improved vibratable supports for the vibratedscreen deck. One object of the invention is to provide improved meansfor securing spring leaves, for such a screen, to the deck and to thescreen base respectively.

Another object is to provide such securing meansfor the-spring leaves aswillprevent the necessity vof perforating or otherwise weakening thespring leaves. Another object is to provide means for readily removingindividual spring leaves or groups of spring leaves without dismantlingthe screen as a whole. f

Otherobjects will appear from time to time throughout the specicationand claims.

My invention is illustrated more or less diagrammatically in theaccompanying drawings, wherein:

Figure 1 is a side elevation with parts broken away and parts inlongitudinal section;

Figure 2 is an enlarged transverse section with parts omitted taken onthe line 2 2 of Figure 1;r

`Figure 3 is a section ywith parts broken away taken on the line 3-3 ofFigure 2;

Figure 4 is a section along the line 4--4 of Fig. 3;

Figure 5 is a section on an enlarged scale takenr along the line 5--5 ofFigure 4;

rFigure is a vertical section through the end of the screen illustratingthe application of similar securing means to another portion of thescreen.

Figure '7 is a section, on anenlarged scale, through one of the boxes orsockets shown in Fig. 6, and Figure 8 is a section on' the line 8-8 ofFig. '7.r I

Referring to the drawings, I generally'indicates any suitable support orloor surface upon which the screen' structure asa whole may be mounted.2 generally indicatesabasewhich may include a plurality oflongitudinally extending side members 3 and transversely extending crossmembers 4. f y

While my spring supports may be applied to a plurality of screens ofdifferent types, I illustrate the invention herein as employed in abalanced screen, in which the screen deck, generally indicated as A,vibrates in opposition to a weight structure generally indicated as B,both. supported on the base 2, by means of the below described`supporting springleaves. The weight structure B may include a pair oflongitudinally` extending weight bars 5 which may be secured together asby the end structure 6, carrying the feed box l, and vibrates as a unit.Any suitable means not herein described in detail, may be employedA formoving the weight structure and the deck at a rapid speed in oppositedirections I illustrate for example, any suitable motor l0 mounted onthe base 2 and provided with a drive pulley Il;

about which passes a belt i2, which," in turn, passes about a drivenpulley I3, which drives any suitable rotor structure Illa, having aneccentric element. It rotates in a housing I4. Any suitable eye passesabout the eccentric and issecured to the opposite of the two vibratedmembers. Thus in response to rotation of the motor, the eiectivedistance between the two vibrated members A andB is varied at a ratedepending' upon the rate of rotation of the rotor Ma.

Referring to the invention, I illustrate a plurality of socket membersl1 located on the base. Each vsuch socket member has a correspondingsocket member on either the weight structure B or the screen deck A.vThe sockets may be welded in place, or otherwise secured Referringi'lrst to the sockets on the base 2, each such socket is in effect a boxhaving a closed bottom plate I5, an endwall IB perpendicular to thebottom plate I5,v side ,walls Il, perpendicular to the bottom plate I5,andan end wall I8 having an inclined face I9. The

bottom plate I5 is also provided with an aperture 20 which, when thedevice is in use, is norwedge 25 may be screw threaded as at 2l toreceive an actuating screw VV28, the head 29 of which abuts against'the. plate 22 kand may bel provided with any suitable spring or lockwasher 3D. It will be understood that in response toi rotation of thescrew 28 in the appropriate direction, the wedge 25 is drawn toward thebottom plate '|5. The result is to lock the lower ends of the springs,and the appropriate spacers, rm-

1y in position in the socket.

The upper ends'of the springs, with corresponding 'spacers are mountedin similar sockets which are secured to the screen deck A or the'weights B, as the case may be. These upperl sockets are identical withthe lower sockets except that'their are inverted, and do not call forfurther description.

In the use of the device, it will be understood that a group of springleaves is inserted into each of the sockets along the base 2. Thesespring leaves, with their appropriate spacers, are then tightened inposition by actuation of the Wedge of each socket. Tightening of thewedge also serves to hold the plate 22 in position to close the bottomaperture 20. The screen deck, or the weight structure as the oase maybe, is then posi-'- tioned on the upper ends of the sprin-gs and theupper spring ends, with their appropriate spacers' 24 are locked in thesockets by the wedges 25 of the upper sockets. l

It will be understood that once the screen has been completed and isready for use, or has been used, any particular spring leaf unit, can bequickly and easily disassembled for new leaves.

It happens that leaves sometimes break in use. L

Where one or more of a group of leaves does break, a leaf or group ofleaves can be readily removed from and replaced in the screen with'- outdisassembling the screen as a whole, All that is necessary is to releasethe wedges 25 at the upper and lower ends of the particular spring leafgroup which is to be removed. As a matter of convenience, the plate 22Iof the upper socket may, for example, be entirely removed or swung outof alignment with the aperture 2li. Then the leaf or leaves can be drawnout through the aperture and replaced. This makes it unnecessary torelease more than the particular set of spring leaves which are beingchecked or re moved. The opening in the plate to accommodate the bolt 28may be enlarged or elongated to ac'- commodate the lateral movement ofthe wedge as it is drawn up, instead of allowing the clearance shownbetween the projection 2| and the aper-A ture 20.

A further advantage is the avoidance of the necessity of aperturingspring leaves to pass securing bolts therethrough, as has been the pastcustom in using spring leaves of this type, Avoiding the use of drilledopenings in the leaves of hardened steel, reduces the cost of springleaves. Further, the avoidance of the drilled openings eliminates orconsiderably reduces spring leaf breakage. It is well known thatstresses tend to concentrate about any opening. The piercing of the endsof the spring leaves very substantially reduces the strength of theleaves and provides a center of strain where the leaf tends to give way.

The present invention diminishes the work andv expense of initiallyassembling the springs and vastly increases the ease, speed and economyof servicing the screen when weakening or breakage of the spring leavestakes place. As above pointed out, the tendency of the spring leaves tobreak is radically reduced. 1

In the structure in which leaf vsprings are bolted to the screen deck orbase by passing bolts through openings in the leaves of the spring, thesteel must be drilled prior to tempering it. Heat treatment distortssteel and gives rmisalignment of the holes. In assembling the springs,it has been found that the last bolt in the assembly usually fitsextremely tightly because of misalignment of the holes and makesitnecessary to drive the. last bolt in place. It thereby sets up aninitial strain in the leaf springs which contributes greatly to theirfailure. This is avoided in the present structure. k

It will be understood that the spacers are held in place only by thefriction exerted by the wedge 25 and can readily be inserted or removedwhen the wedge is released. It will also be understood that the socketsmay take spring leaves of varying thickness and in varying numbers bythe use of any suitable shims or spacers of varying thicknessandnurnber.l

Referring to Figures 6 to 8, I illustrate the invention as applied tothe springs connecting the sidebar weight structure and the deck.Referring to Fig. 6, the deck is generally indicated as A1 and the sidebar structure as B1. lt will be understoodthat Mb generally indicates ahousing for the vibrating or eccentric mechanism, the details of whichdo not form part of the present information. This housing is connectedto the deck structure A1 by the springs below described. In the housingrotates any suitable rotor or eccentric not herein shown and not ofitself forming a part of the present invention. It will be understoodthat an appropriate connection between Vsuch rotor and the weightvstructure B1 is provided,I so that in response to the rotation of therotor, the weight structure B1 and the deck 1 structure A1 are vibratedin opposition to each other. The housing Mb and the opposed end of thedeck A1 are provided with opposed sockets or boxes shown in detail inFigure '7, and of somewhat stronger or heavier construction than thecorresponding boxes or sockets I1. Each such box includes a rear orbottom wall 5l), a side wall 5| perpendicular thereto, other side walls52 per- ;pendicular both to 50 and to 5| and a slightly inclined sidewall 53, adapted to engage the inclined face of the wedge 54. Thus, alive-sided box is provided, into the open end of which is inserted aplurality of spring leaves and spacers 55a. These leaves are hereinshown as having thicker spacers 56 at each side of the spring group. Thebottom 50 has an aperture 51 of sufficient width to permit individualspring leaves and spacers to be withdrawn therethrough if necessary.`The wedge 54 has a face 58 which is perpendicular to the bottrn 50. Itsopposed inclined face 59 con forms to the inner face of the inclinedWall 53. The wedge may be provided lwith an aperture 60 `extendingentirely therethrough. The wedge may be drawn into position by a bolt 6|having head 62 engaging the lar-ge end of the wedge. Preferably thediameter of the belt is somewhat less than vthe diameter of the aperture6D. 63 is a closure plate having a lug 63a penetrating the aperture 51.The bottom 5D and the closure plate 63 `are penetrated by apertures 64and 65 respectively, which are both of greater diameter than the bolt6|. 66 is any suitable lock washer or Washer, and 61 is a nut fordrawing up the bolt 5|. It will be understood that the groups of springleaves 55 may lieemployed in @pairs at each end of the housing Mb s'othat four sets may constitute a complete connection between the deckstructure A1 and the housing |4b.

It' will be realized that while I have shown and described an operativedevice, still many changes in size, shape, arrangement number anddisposition of parts might be made without departing materially from thespirit of my invention. I wish, therefore, that my 4showing be taken asin a broad sense diagrammatic.

The use and operation of the invention are as follows:

I illustrate an improvement lin securing means for the ends of leafsprings or groups of leaf springs, which is particularly applicable to,but not groups of spring leaves 23 which t at theirends into boxes orsockets on the base structure andv on the weight structure and thedeckstructure respectively. While my inventiony may be'applied to a widevariety of screens, the particular type herein shown is vibrated by 'arotor actuated by a motor yIt'l on the base. 13 is a driven y pulley forrotating the'rotor. The rotor maybe rotatedly mounted in any vsuitablehousing Ma.

The details of the rotor do not form part of the present invention, butit Will be understood that the housing Ma is flexibly secured to thedeck' structure A as by the spring leaves 55 of Fig. 6,'

and that the rotor includes an eccentric connection with' the Weightstructure B. Thus in response to rotation of the rotor both the weightstructure and the deck structure are vibrated but in oppositedirections.

An important advantage of my invention` is the prevention of breakageresulting from the avoidance of any necessity of drilling holes throughthe spring leaves. The steel must be drilled prior to tempering it, andheat treatment distorts the steel and misaligns the holes. Therefore,the avoidance of any necessity of drilling holes through the springleaves materially adds to the life and strength of the leaves.

In the spring leaves .55, the tendency to slip because of the forcesexerted lengthwise of the spring maybe substantial. To counteract this Iemploy a substantially stronger box around the spring leaves, and inpractice, somewhat decrease the angle of the wedge to. increase theclamping action. It must bek remembered that the forces tendingto shiftthe leaf springs laterally are very large and that in bending the groupso-f springs the outer leaf of the convex side of the defracted groupwill be too short to accommodate the length of the inner leaf on theconcave side. Thus. the forces tending to cause slippage become verylarge. However, I find that the structure herein shown is adequatefirmly to hold the spring leaves. I have shown, in connection with Fig.6 and the leaves 55, the use of a through-going bolt BI.

rIhis has an advantage, in that in tightening a nutwith ya wrench thereis a tendency to slip the nut laterally, as -but rarely does a nut lieflat against the washer or an abutting surface. This,

in turn, may tend to bend the structure and tend to break the stud orlbolt in junction with the wedge. The through-going bolt structure ofFig. 6 eliminates this weakness, and it will be understood that, ifdesired, this type of bolt may be employed also with the sockets orboxes i1 on lthe base and on the weight structure and deck structure. Iclaim: l. In spring supporting means for a vbrated screen deck, a baseelement, a plurality of up-v wardly open sockets therein, having sideand end walls, a deck having a plurality of downwardly open sockets,vhaving side and end walls, one or more flat spring leaves for eachopposed pair of sockets, the upper ends of whichk extend into a socketon the deck, the lower ends ends normally extend, each having anaperture of suincient size to permit the insertion or Withdrawal of aleaf therethrough. v

2. In a supporting spring assembly for vibrated members, a supportingmember, a vibratable member, opposed sockets on the two members, one

or more iiat spring leaves the opposite ends of which-extend kinto saidsockets, each said socket having a Wall, the face of which is generallyparof whichk extend into a corresponding socket on the base, andclamping means associatedV with such Sockets for clamping said leaf endsin re lation to the sockets, the end walls of the sockets, opposite thesocket opening into which the leaf alle'l with the side faces of saidleaves, and an opposite wall having an inclined face, a Wedge element insaid socket, having a face opposed to and parallel with said parallelfaced wall, and an inclined face opposed to the inclined face of saidinclined faced wall, the spring ends being `located' between saidopposed parallel faces, and

means for moving the Wedge element along the inclined face, and forthereby clamping the leaf ends in relation to thev socket, the sockethaving a wall, opposite its opening into which the leaf ends normallyextend, having an aperture adapted for the passage therethrough of saidleaf or leaves,

3. In a supporting spring assembly for vibrated members, a supportingmember, a vibratable member, opposed sockets on the two Vmembers, one ormore fiat 'spring leaves the opposite ends of which extend into saidsockets, each said socket having a wall, the -face of which is generallyparallel with the side faces of said leaves, and an opposite wall havingan inclined face, a wedge element in said socket, having a face opnposed to and parallel with said parallel faced wall, and an vinclinedface opposed to the in clined face of said inclined faced Wall, thelspring ends being located between said opposed parallel faces, and meansfor moving the wedge element along the inclined face, and for therebyclamping the leaf ends in relation to the socket, the socket having awall, opposite its opening, into which the leaf ends normally extend,having an aperture adapted for the passage therethrouglci` of said leafor leaves, and means for normally closing said aperture. y 4. In asupporting spring assembly for vibrated `members, a suporting member, avibratable an inclined face opposed to the inclined face of` saidinclined faced wall, the spring ends being located between said opposedparallelfaces, and means for moving the wedge element along the inclinedface, and for thereby clamping-the leaf ends-in relation to the socket,the socket having a Wall, opposite its opening, having an apertureadapted for the passage therethrough of said leaf `or leaves, and means`for normally closing said aperture, including a plate having anextension penetrating said aperture, and an actuating. screw for saidwedge element penetrating said plate.v

5. In combination, a set of flat spring leaves and means for securingthe ends thereof, including a pair of opposed boxes, each having abottom wall and sidewalls extending therefrom, said leaf springs beingat their ends inserted in said boxes, at least one wall of said boxesbeing parallel with the flat faces of the spring leaves, and wedge meansin each said box, adapted to clamp said spring leaves against saidparallel Wall,

said bottom wall having an aperature therein of suincient size to permitthe spring leaves to be Withdrawn therethrough, and means for normallyclosing said aperture.

6. In combination, a set of flat spring leaves and means for securingthe ends thereof, including a pair of opposed boxes, each having abottom wall and sidewalls extending therefrom, said leaf springs beingat their ends inserted in said boxes, at least one wall of said boxesbeing parallel with the flat faces of the spring leaves, and wedge meansin each said box, adapted to clamp said spring leaves against saidparallel wall, said bottom wall having an aperture therein of a.sufficient size to permit the spring leaves to be withdrawn therethroughand a cover plate therefor, having a portion closing said aperture.

'7. In combination, a set of spring leaves and means for securing theends thereof, including a pair of opposed boxes, each having a -bottomwall and sidewalls extending therefrom, said leaf springs being at theirends inserted in said boxes, at least one wall of each of said boxesbeing parallel with the fiat faces of the spring leaves, and wedge meansin each said box, adapted to clamp said spring leaves against saidparallel wall, including a wedge in each box, having a face paralllel tosaid -parallel wall, opposed to said leaf springs, and an oppositeinclined face opposed to the wall of the box opposite to said parallelwall, said opposite wall having an inclined face opposed to the inclinedface of the wedge, and means for imparting movement to said Wedge,incuding a bolt passing longitudinally through the wedge and having anVabutment opposed to the large end thereof, said bolt passing throughthe bottom wall of the box, and an exterior actuating nut therefor, saidbottom wall having an aperture therein of suiiicient size to permit thespring leaves to be withdrawn therethrough, and a cover plate therefor,having a portion closing said aperture, the bolt passing through saidcover plate, the nut being adapted to exert a thrust thereagainst.

8. In a spring supporting unit for vibrated members, a base element,.anupwardly open socket on said base element, a vibrated element, adownwardly open socket onsaid vibrazted element, one or more generallyflat spring leaves, the opposite ends of said leaves extending into saidopposite sockets, one of said sockets having an aperture in the wallopposite to the socket opening into which the leaf ends normally extend,of a size and shape adapted to permit the insertion of a leaftherethrough, and means for normally closing said aperture and forpreventing the escape of a leaf therethrough.

9. In ak spring supporting unit for vibrated members, a base element, anupwardly open socket n said base element, a vibrated element, adownwardly open socket on said vibrated element, one or more generallyilat spring leaves, the.op posite ends of said leaves extending intosaid opposite sockets, one of said sockets having an apern ture in thewall opposite to the socket opening into which the leaf ends normallyextend,l of a size and shape adapted to permit the insertion of a leaftherethrough, wedge means positioned in said socket and means for movingit longitudinally along said spring leaves toward the wall of saidsocket in which said aperture is located.

10. In a spring supporting unit for vibrated members, a base element, anupwardly open socket on said base element. a vibrated element, a

downwardly open socket ony said vibrated element, one or more generallyflat spring leaves, the opposite ends of said leaves extending into saidopposite sockets, one of said sockets having an aperture in the wallopposite to the socket opening into which the leaf ends normally extend,of a size and shape adapted to permit the insertion of a leaftherethrough, wedge means in said socket, for locking said leaves, aclosure element for normally closing said aperture and a locking elementadapted simultaneously to urge said wedge means toward leaf securingposition and to urge said closure toward closing position.

11. In spring securing means for a vibrated screen deck, a. socketincluding side walls surrounding a spring end receiving space and havingan open end adapted to permit the insertion of a spring ends, and aclosed end, said closed end having an aperture therein of a size andshape adapted to permit the insertion or removal therethrough of aspring leaf, one of the ,side walls having a wedge surface inclined tothe surface of the opposite side wall, a wedge adapted to be insertedbetween said wedge surface and the spring ends, and means for urgingsaid wedge toward the closed end of the socket and for thereby lockingthe spring ends in said socket.

12. In spring securing means for a vibrated screen deck, a socketincluding side walls surrounding a spring end receiving space and havingan open end adapted to permit the insertion of spring ends, and a closedend, said closed end having an aperture therein of a size and shapeadapted to ypermit the insertion or removal therethrough of a springleaf, one of the side walls having a wedge surface inclined to thesurface of the opposite side Wall, a wedge adapted to be insertedbetween said wedge surface and the spring ends, means for .urging saidwedge toward the closed end of the socket and for thereby locking thespring ends in said socket, and means for nor- Inally closing theaperture in the end wall of the socket.

13. In spring supporting means for a, vibrated screen deck, a baseelement and a deck, one of said elements having thereon a plurality ofsockets, each of said sockets having side walls and an end wall, one ormore flat spring leaves, the ends of which extend into each said socket,and clamping means associated with said sockets for clamping the leafends in relation to the sockets, the end walls of the sockets oppositethe opening into which the leaf ends normally extend, each having anaperture of sufficient size to permit the insertion or withdrawal of aleaf therethrough.

14. In spring supporting means for a vibrated screen deck, a baseelement and a deck, one of said elements having thereon a plurality ofsockets, each said socket having side walls and an end wall, one or moreflat spring leaves, the ends of which extend into each said socket,clamping means associated with said sockets for clamping the leaf endsin relation to the sockets, the end walls of the sockets opposite theopening into which the leaf ends normally extend, each having anaperture of sufficient size to permit the insertion or withdrawal of aleaf therethrough, a tapered clamping means including a clamp memberinsertible in said socket, and means for withdrawing said clamp membertoward the closed end of the socket.

JOHN L. RAPP.

